H7N9 may mutate 8 times faster than regular flu
The new bird flu could be mutating up to eight times faster than an average flu virus around a protein that binds it to humans, a team of research scientists in Shenzhen says.
Dr He Jiankui, an associate professor at South University of Science and Technology of China, said yesterday that the authorities should be alarmed by the results of their research and step up monitoring and control efforts to prevent a possible pandemic.
With genetic code of the virus obtained from mainland authorities, the team scrutinised haemagglutinin, a protein that plays a crucial rule in the process of infection. The protein binds the virus to an animal cell, such as respiratory cells in humans, and bores a hole in the cell's membrane to allow entry by the virus.
The researchers found dramatic mutation of haemagglutinin in one of the four flu strains released for study by the central government. Nine of the protein's 560 amino acids had changed. In a typical flu virus, only one or two amino acids could change in such a short period of time, He said.
"It happened in just one or two weeks. The speed may not have caught up with the HIV, but it's quite unusual for a flu."
The fast mutation makes the virus' evolutionary development very hard to predict. "We don't know whether it will evolve into something harmless or dangerous," He said. "Our samples are too limited. But the authorities should definitely be alarmed and get prepared for the worst-case scenario."
The origin of the virus was puzzling due to its novelty, but He's research suggested some clues that differ from the mainland authorities' theories.
His team compared the new virus strain to all other H7N9 viruses identified in Europe and in other Asian countries that were cited by the Ministry of Agriculture as possible origins of the new bird flu, but found them all very different.
In fact, the new bird flu was quite similar to some familiar domestic viruses such as H9N2, H11N9 and H7N3 found in Zhejiang and Jiangsu.
He said researchers could not rule out the possibility that the new virus was carried into China by wild birds, but it was more likely to be of local origin.